<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8" />
		<title></title>
	</head>
	<body>
		
	</body>
	
	<script>
		//1  1  2   3   5   8  13  21  34  55  89
		
		//f(n) = f(n-1) + f(n-2)  n>=3
		
		function f(n){
			if(n<3) return 1;
			return f(n-1) + f(n-2);
		}
		
		
	</script>
	
</html>